Manufacture of readily-soluble tanning preparations



Patented Nov. 4, 1924.

UNITED STATES PATENT OFFICE.

CARL IMMERHEISER, OF LUDWIGSHAFEN-ON-RHINE, AND FRANZ HASSLER, OF HAM- BURG, GERMANY, ASSIGNORS, BY MESNE ASSIGNMENTS, TO ROI-1M & HAAS COM- PANY, OF PHILADELPHIA, PENNSYLVANIA, A CORPORATION OF DELAWARE.

MANUFACTURE OF READILY-SOLUBLE TANNING PREPARATIONS.

No Drawing.

To all whom it may concern:

Be it known that we, CARL IMMERHEISER and FRANZ HASSLER, citizens of the German Empire, residing at Ludwigshafen-on-Rhinc and Hamburg, respectively, Germany, have invented new and useful Improvements in the Manufacture of Readily-Soluble Tanning Preparations, of which the following is a specification.

As is known, natural tanning bodies are sometimes insufiiciently soluble, and the extraction from materials containing such bodies ofi'ers certain difiiculties. The specification of Letters Patent 1,133,108 discloses a process for converting insoluble, or insufficiently soluble, natural tanning extracts into products readily soluble in water, b adding to them certain condensation pro ucts possessing phenolic, hydroxyl and salt-forming, groups, whilst the specification of Letters Patent 1,216,612 describes the use, for the same purpose, of aromatic sulfonic acids of an amorphous character, which are free from phenol, quinone and quinone-imid groups, are soluble in water and capable of precipitating glue, or gelatin, from solutions.

Now we have found that readily soluble tanning preparations can be advantageously produced by extracting tanning bodies from vegetable materials containing them with solutions of aromatic sulfonic acids, either of an amorphous or. of a crystalline character, and either possessing, or being free from, phenolic groups, but which are capable of precipitating glue, or gelatin, from acid solutions. The extraction with the aforesaid solutions can take place eitherdirectly or it may be combined with a preceding extracting process according to usual, or any suitable, methods.

As instances of sulfonic acids that may be employed for the process according to this invention we mention those described in the specifications of Letters Patent Nos. 1,130,500, 1,101,430, 1,203,009, 1,222,033, 1,232,020, 1,230,759, 1,237,405, 1,254,304,

1,278,229 1,281,494 and 1,289,280, but any other sulfonic acids capable of precipitating glue, or gelatin, from acid solutions are equally suitable. The said sulfonic acids can be used in the free state or as salts, preferably as alkali salts.

The term aromati sulfonic acid wher- Serial No. 395,126.

ever it occurs in this specification does not include lignin sulfonic acids or ligno sulfonates or similar compounds extracted from wood by the action of disultites which compounds sometimes are reported to be of an aromatic nature though they are of a peculiar nature and very widely different. from the true aromatic compounds.

By this process the extraction of tannin from tannin-bearing woods and the-like is considerably accelerated and the yield increased. Besides, as the sulfonic acids employed have tanning properties for themselves, the tanning properties of the products obtained by the aforesaid process are improved. Having in view that most of the sulfonic acids defined will develop their tanning properties in an acid solution only, the employment of the products for tanningv when they are prepared according to the present process with the. aid of sulfonic acid salts may be carried out while adding a limited amount of an acid. The tanning process will proceed in a comparatively short time and a light-colored leather will be produced.

The invention is further illustrated by the following example to which however it is not confined. The parts areby weight E mample.

The vegetable tanning material, for example quebracho wood, serving for the preparation of tanning juices, or extracts, after being suitably ground, is subjected, in the usual extraction apparatus, to treatment with a hot aqueous solution of about 1 Baum of the condensation product of sulfonated naphthalene and formaldehyde as described in the Example 2 of the specification of Letters Patent l\o. 1,191,480. When the first extract rich in tanning compounds is taken off, the extraction can be repeated in a suitable manner until the material is completely exhausted.

A vegetable material treated as aforede scribed, or a material which has been more or less exhausted by treating with water, or with weak tanning juices or with other extracting means, is subjected at about from 90 to 100 degrees centigrade to treatment for a short time with a solution of about 1 Baum of the partially neutralized condensation product from sulfonated phenol and formaldehyde asfdescrihed in Example .1 of the specification of Letters Patent No. 1,237,- 405. In order to completely remove the products left in the extracting juice, which is retained by the tanning material, the latter is then subj ected to treatment with pure Water at boiling point. The juices thus obtained'can be-employed for preparatory tanning purposes or in further extraction operations. In either case the solutions of tanning substances obtained according to the present process can he used for tanning directly or they canbe evaporated to a-concentrated or even solid condition.

Other products of the aforedefined character, for'instance sulfonic acids of anthracene, or carbazol, or of mixtures or raw-prod uctsof'both, can be employed in a similar manner. Vegetable materials 1 containing tanning bodies other than quebracho wood can. also be used.

We claim 1. The process ofmanufacturing readilye soluble tanning preparations by treating vegetable materials containing Jcanning hodies'wlth solutions of an aromatic sulfonic 1 acid capable of precipitating glue from acid solutions.

ZQThe process of manufacturing readily soluble tanning preparations by treating vegetable materials containing tanning.

bodies with solutions of a saltof an'a'romatic sulfonic acid capable of precipitatingglue from acid solutions.

3 The process of manufacturing readily soluble tanning preparations by treating vegetable materials containing tannin bodies with a solution of s it of sulfonate crude anthracene. 4. The process of manufacturing readily soluble tanning preparations by treating a tannin bearing wood with an aqueous solution of an aromatic sulfonic acid capable of precipitating glue from acidsoluset our hands.

' a ali 1|; RHEISER.

DB. CARL FRANZ SSL. 

